Communications cable systems normally include a plurality of discrete cable lengths which are joined together at splice locations and which are joined to other apparatus at terminal points. Each of these discrete cable lengths comprises a multi-conductor or optical fiber core that may be enclosed in a relatively thin metallic shield, and an outer plastic jacket. The shield typically takes the form of a metallic tape that is wrapped longitudinally about the core to form a tubular member having an overlapped seam.
A metallic shield in communications cables performs a variety of important functions. Some of these are the protection of craftspersons from injury and of equipment from damage if a live power line should fall and contact the cable, protection from inductive pickup due to power line voltage, protection from lightning and suppression of radio frequency pickup. The metallic shield also provides physical protection of the cable core and acts as a barrier to moisture penetration.
To obtain effective shielding from power line-induced noise, for example, shield continuity must be provided throughout the cable. At splice locations where the cable jacket and shield are removed to expose the individual conductors, it becomes necessary to provide for continuity of the shield across the splice locations for proper electrical protection of the conductors. Moreover, it is not uncommon for a cable shield to be earth grounded. Connection to the cable shield at splice locations is generally accomplished with shield clamping device which is referred to in the art as a bond clamp or bonding device. Bonding devices on opposite sides of the splice are interconnected.
One prior art bonding device for use in providing electrical cable shield continuity clamps directly onto the relatively thin shield; however, such a device may tear or damage the thin conductive shield and thereby lose its effectiveness. Another bonding device Pat. No. 3,499,972, includes a base which fits beneath the shield and which has a stud protruding outwardly through a slit which is cut in the shield and in an overlying outer jacket. An outer bridge is mounted on the stud to clamp the shield and jacket between the base and the bridge.
Still another cable shield connector comprises an inner plate having an upstanding tab on one end thereof, and an outwardly protruding threaded stud spaced from the tab. The opposite end of the inner plate is slipped under the shield until the stud abuts the ends of the shield and jacket and an outer plate is positioned on the stud over the jacket and forced toward the inner plate by a nut which is turned along the stud. The outer plate first contacts the upstanding tab of the inner plate and tends to pivot thereabout causing the other ends of the plates to tightly clamp the shield and jacket therebetween. Such a cable shield connector is disclosed and claimed in U.S. Pat. No. Re 28,468 which was issued on Jul. 8, 1975 in the names of R. G. Baumgartner et al.
Often times, the bonding device, as it is termed in the art, is disposed within the confines of a closure. Desirably, the sought-after connecting device is closure independent, that is the connecting device is not structured to conform to any particular closure structure but rather is capable of being used in a multitude of closures.
Also, a further problem exists with respect to optical fiber cables. In that art, it is not uncommon to find some manufacture's cables which include a plurality of longitudinally extending strength members which are made of a metallic material. If such strength members are included in a cable to be spliced, they too must be connected electrically to the ground connection which is carried across the splice. The prior art bonding devices described herein are not capable of establishing electrical connections with metallic strength members of cable.
Clearly, there is a need for a connecting device which is used to establish electrical continuity of a shield across a cable splice. Also, the sought after device should be capable of connecting electrically and mechanically to one or more strength members of a cable sheath system. Seemingly, the prior art does not show a connector which fulfills these needs.